On 2018-08-08 14:48:54
laser heat treatment technological principle
Laser heat treatment
Speaking of laser heat treatment, we should all be familiar because we have all heard of it. In fact, as a high-frequency heat treatment technology, laser heat treatment technology is not only suitable for industry fields, such as stamping mold, injection mold, auto parts, but also for shipbuilding, steel, machinery, electronic industry and other fields, and its application scope is gradually expanded to multiple fields that need local heat treatment to improve product hardness and strength.
Heat treatment "refers to the method of changing the structure or properties of metal materials in various ways by heating them. Although the photoheat treatment technology is similar to the existing high-frequency heat treatment method in inducing the change of the surface structure, the laser heat treatment method has more advantages. For example, after the laser heat treatment, the size change of the base metal is almost zero, and the surface hardness becomes higher due to the formation of more compact structure without additional cooling engineering. Laser heat treatment technology can also carry out selective heat treatment for the required parts, such as three-dimensional shape of mechanical accessories and mold products, cutting] blade not end special parts, etc. At the same time, by using pyrometer to measure and control the surface temperature of base metal in real time, stable heat treatment quality can be obtained in a large number of small batch production projects.
After laser heat treatment, the surface hardness will be different according to the carbon content of the base metal, which is usually kept at the level of > 5365hc, the effective hardening depth is about 0.8 ^ 1.5m, and the hardening range is adjusted to several millimeters to dozens of millimeters according to the laser power. Up to the beginning of 2000, CO2 laser was mainly used in laser heat treatment engineering. However, with the development of many kinds of high-power lasers in China, high-power lasers with higher absorptivity for metal materials were favored, including semiconductor lasers, disk lasers and fiber lasers, which were used for heat treatment to improve the hardness and strength of products.
As far as the basic principle of laser metal heat treatment technology is concerned, by irradiating the high energy density laser beam on the surface of metal material, the temperature of the base metal rises sharply to the point where the temperature of the base metal is about to reach the temperature kitchen inch, and it cools rapidly again, thus inducing the change of the surface structure. The laser irradiation on the surface of the base metal will be converted into heat energy, which will heat the surface of the base metal, and reduce the temperature again by using the heat conduction characteristics of the base metal, and finally improve the hardness and strength of the material.